Method and apparatus for diagnosing and treating neural dysfunction

ABSTRACT

A method and apparatus for diagnosing and treating neural dysfunction is disclosed. This device has the capability of delivering the therapeutic electrical energy to more than one treatment electrode simultaneously. In another exemplary embodiment, this device can perform EMG testing both before and after the therapeutic energy has been delivered, to assess whether the target nerve was successfully treated. In another embodiment, the device has the capability to record and store sensory stimulation thresholds both before and after treatment is described, which allows the clinician to accurately determine whether the target nerve has been desensitized. Energy control may achieved by simultaneously comparing the tip temperature of each treatment electrode to a set temperature selected by the operator, and regulating the therapeutic energy output to maintain the set temperature. In another embodiment, EMG, stimulation thresholds, and graphs of temperature versus time can be conveniently displayed on a two-dimensional graphics display.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/185,646, filed Jul. 19, 2011 and titled “Method and Apparatus forDiagnosis and Treating Neural Dysfunction”, which is a continuation ofU.S. patent application Ser. No. 12/966,550, filed on Dec. 13, 2010,which issued as U.S. Pat. No. 8,000,785 on Aug. 16, 2011, which is acontinuation of U.S. patent application Ser. No. 12/501,074 filed onJul. 10, 2009, which issued as U.S. Pat. No. 7,853,326 on Dec. 14, 2010,which is a continuation of U.S. patent application Ser. No. 11/498,446filed on Aug. 2, 2006, which issued as U.S. Pat. No. 7,574,257 on Aug.11, 2009, and which claims priority to U.S. Provisional PatentApplication No. 60/704,849, filed on Aug. 2, 2005, the entiredisclosures of which are hereby incorporated herein by reference.

FIELD

The presently described system relates generally to the advancement ofmedical technology, processes, and systems for the treatment of pain,neurological disorders, and other clinical maladies related to neuraldysfunction. More specifically, the present disclosure is directed at asystem for producing therapeutic lesions or tissue alterations by meansof a high frequency generator connected to a patient via more than oneelectrode. In below-described exemplary embodiments, therapeutic energyis delivered and regulated simultaneously. Various specific exemplaryembodiments of this device accommodate specific exemplary clinicalapplications and designs.

BACKGROUND

The general use of radiofrequency and high frequency generator systemswhich deliver electrical output to electrodes that are connected to apatient's body is known in the clinical literature and art.

By reference, an example of radiofrequency heat lesioning generatorsused in clinical practice for the treatment of neural disorders is theRadionics RFG-3C+ (Burlington Mass.).

This device is capable of delivering high frequency energy to patienttissue via an adapted electrode, and associated ground or referenceelectrode. This device is also capable of delivering low frequencystimulation pulses that are used to accurately localize the electrodeplacement before treatment.

Parameters that may be measured by these devices include impedance, HFvoltage, HF current, HF power, and electrode tip temperature. Parametersthat may be set by the user include time of energy delivery, desiredelectrode temperature, stimulation frequencies and durations, and levelof stimulation output. In general, electrode temperature is a parameterthat may be controlled by the regulation of high frequency output power.

These devices have various user interfaces that allow the selection ofone or more of these treatment parameters, as well as various methods todisplay the parameters mentioned above.

In one application of these devices, a patient complains of back pain,or some other pain of nocioceptive or neuropathic origin. A doctor thenperforms diagnostic blocks with local anesthetic by injecting theanesthetic into the areas that is suspected of generating the pain. Ifthe patient receives temporary relief from these injections the doctorconcludes that the pain generators were in the location where he madethese injections. Unfortunately, the origin of pain is poorlyunderstood; perceived pain at a certain level in the back, for instance,can actually be created from many different and multiple sources.

Once a location has been identified, the clinician will decide todeliver high frequency energy to this location to permanently destroythe pain generator. A ground or reference plate will be placed on thepatient's thigh to provide a return path for the high frequency energy.An insulated electrode with a small un-insulated tip will be placed atthe expected target. Stimulation pulses will be delivered at a sensoryfrequency (typically 50 Hz), and a stimulation voltage will be placed onthe electrode. The clinician is looking for a very low threshold ofresponse from the patient (e.g., less than 0.5 V) to ensure that theelectrode is close to the sensory nerves. They will then perform astimulation test at a muscle motor frequency (e.g., 2 Hz), and increasethe stimulation voltage output to 2 v. In this instance, they arelooking for no motor response in the patient's extremities as this wouldindicate the electrode was too close to the motor nerves. Treatment inthis area could cause paralysis. Upon successful completion of thesetests, high frequency energy is typically delivered for one or moreminutes, while maintaining an electrode tip temperature between 70 and90 degrees. Alternatively, high frequency energy may be delivered forone or more minutes, but in a pulsed mode where the high frequencyenergy is on for a short period of time and off for a long period oftime, thus not producing any appreciable heating (reference is made tocommonly assigned U.S. Pat. No. 6,161,048, the entire contents of whichare specifically incorporated by reference herein).

Although these treatments are successful, they have several drawbacks.In practice, most patients need treatments at several different nervelocations. This requires placing the electrode, performing thestimulation, and delivering the energy at each location and thenrepeating the process, thus causing a great deal of wasted time, andpatient discomfort, while waiting for the energy to be delivered.Another drawback is that in spite of successful stimulation testing, thetarget nerve is often not destroyed resulting in no decrease of pain.The clinician is left to determine whether the target nerve has beenmissed, or whether the pain generator is located else where in the body.

SUMMARY

The above-described and other disadvantages of the art are overcome andalleviated by the present method and system for taking the energy outputfrom a high frequency generator module and delivering this energysimultaneously to more than one treatment electrode. In one exemplaryembodiment, the energy is regulated by a feedback mechanism such thateach electrode's tip temperature is maintained to a level set by theuser. This greatly reduces treatment time, providing the patient with ashorter period of discomfort as well as not wasting valuable procedureroom time.

In additional exemplary embodiments, EMG measurements are displayed toallow the clinician to determine whether the target nerve has beendestroyed, as well as the display of pre-treatment and post-treatmentsensory stimulation thresholds to measure the degree of desensitation ofthe target nerve. Regarding the EMG measurements, this allows theclinician to determine whether the target nerve has been successfullytreated; if it has been, then other pain generation sources need to beinvestigated. The capability of being able to compare pre-treatment andpost-treatment sensory stimulation thresholds gives the clinician animmediate look at the immediate desensitation of the target nerve.

In accordance with one exemplary embodiment, the device receives inputfrom a module capable of delivering both high frequency energy as wellas low frequency stimulation pulses, such as between 1 and 100 Hz. Thedevice is, in turn, connected to greater than one treatment electrode.These electrodes have temperature sensors attached to their tips, whichreports the tip temperature of each electrode to the device. The devicehas a user interface which allows the output from the said module to beindependently connected to each said electrode and also a means whichconnects all the electrodes simultaneously to the output of the saidmodule. In this way, the low frequency stimulation output can beindependently connected to each of the patient electrodes, and then thesaid electrodes can be connected simultaneously to the high frequencypower source, thus permitting temperature regulation of the threeelectrodes simultaneously. This allows both sensory and motorstimulation testing, as well as impedance monitoring to be performed oneach electrode one at a time. When the therapeutic energy is desired tobe delivered, the user interface allows a means which connects allelectrodes together simultaneously. The device then receives the tiptemperature from each of the multiple electrodes, as well as a settemperature for each electrode that is chosen by the user. The devicecontinually compares each of the temperatures from the electrodes to theset temperature. If the electrode tip temperature ever exceeds the settemperature, the high frequency energy is disconnected from thatelectrode. Similarly, if the electrode tip temperature is ever less thanthe set temperature, the high frequency energy is either left connectedor reconnected to that electrode.

Another exemplary embodiment of this invention incorporates a graphicdisplay, which allows EMG signals to be recorded to and displayed. Anadditional provision allows for a speaker and/or a headphone output sothat the EMG signals can also be audibly detected and analyzed.

It should be noted that the present system and method can beincorporated into high frequency power source, or can be a stand-aloneperipheral device that connects in-between the high frequency powersource and the electrodes.

For at least the reasons described above, this method and inventionprovides practical and clinical advantages in the treatment of pain.Additional advantages will become apparent in the detailed descriptionsthat follow.

The above discussed and other features and advantages of the presentsystem will be appreciated and understood by those skilled in the artfrom the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the figures, which are exemplary embodiments andwherein the like elements are numbered alike:

FIG. 1 represents a simple exemplary embodiment of the presentlydescribed system;

FIG. 2 illustrates an exemplary temperature feedback control mechanism;

FIG. 3 is a schematic illustrating an exemplary setup for how theelectrode set temperature is maintained;

FIG. 4 is another exemplary embodiment showing the representation of thetemperature of each of the electrodes in graphical form;

FIG. 5 is another exemplary embodiment which also illustrates thegraphing of the EMG signal;

FIG. 6 is another exemplary embodiment showing one method ofrepresenting pre and post-treatment sensory stimulation thresholds; and

FIG. 7 is another exemplary embodiment showing three distinct modeselections, as well as an exemplary method for selecting each electrodeindividually and further an exemplary method to record sensorystimulation thresholds.

DETAILED DESCRIPTION

Referring to FIG. 1, an exemplary embodiment is illustrated. Mode selectswitch 20 allows the user to independently connect each electrode, eachof which is identified as 60, to the high frequency power source. Thispermits the high frequency power source to selectively be connected toeach electrode for the purpose of doing individual impedancemeasurements or stimulation threshold testing. An additional selectionon the mode select switch allows therapeutic high frequency energy to bedelivered to each electrode 60. The high frequency energy is deliveredsimultaneously to each electrode and the individual electrodetemperatures are measured and continuously compared to the user settemperature, represented by 40 in FIG. 1. As also shown in FIG. 1, theelectrodes are separate and not connected to one another. In otherwords, the electrodes are separate probes that each incorporate activeelectrode elements. The term “electrode(s)” as used alone hereinafterrefers to a probe(s) having the active electrode element(s). In thisembodiment the individual electrode temperatures are displayed on atwo-dimensional graphics panel identified by 10 in the figure. Alsowithin the graphics display is a representation of temperature vs. timedisplayed in graphic format. Indicator lights, represented by 30 in FIG.1, indicate which electrode is active at that particular moment. In thisway the user always knows which electrode is active when the mode selecthas been set to a particular electrode, and will also indicate duringhigh frequency therapeutic treatment which electrodes are beingactivated at any given time.

It is very important to note two things from this figure—one is that tothe high frequency power source that delivers the high frequency energyand/or low frequency stimulation pulses could be incorporated into thisdevice or could be a separate stand-alone unit, with this deviceinterposed between the high frequency power source and the electrodes.Though the figure shows this device as being AC line connected (that isrequiring an electrical outlet for the unit to be plugged into), abattery-operated device may also be used.

It should also be understood that mode selection could be done in manyways and the features of this user interface could be achieved with orwithout displays, and could use up/down pushbuttons rather thanrotatable selector knobs. For instance, mode select could individuallyconnect each electrode to the high frequency device, and could also havea position which independently connected each electrode to any EMGmeasuring circuit, where the EMG signal was then displayed on atwo-dimensional graphics display. An additional position on the modeselect would be high frequency energy delivery where either continuousor pulsed high frequency energy was delivered simultaneously to eachelectrode and a feedback circuit was incorporated to maintain eachelectrode tip at a temperature equal to set temp.

It should also be noted there are many ergonomic manifestations of thisinvention and it would be possible to add additional displays, buttons,and/or indicators to allow and/or assist the operator in controlling thedevice. For instance, FIG. 1 has an RF on indicator light, representedby 50, which will indicate whenever high frequency energy is beingdelivered to the electrode outputs.

FIG. 2 is a logic control diagram indicating a basic exemplary feedbackmechanism for each of the temperature control electrodes. HF power,identified as 10A in the figure, is delivered system. The temperature ofthe electrode receiving this HF energy, as well as the user settemperature, is measured and a decision point is reached, represented by20A in the figure. If the electrode temperature is greater than the userset temperature, the HF power is turned off to that electrode. Thisaction is represented by block 30A in FIG. 2. Then this process startsall over again, where the electrode temperature is once again comparedto the user set temperature. Conversely, if the measured temperature forthat particular electrode is less than the user set temperature the HFremains on, and again, the electrode temperature is subsequentlycompared to the user set temperature. In this way temperature feedbackis realized, which will maintain the electrode temperature at the samelevel as the user set temperature.

FIG. 3 is a more detailed schematic of an exemplary feedback controlmechanism. Note that this circuit is only representative of the HFenergy delivery, and other connections have been omitted for clarity. Asan illustration of how the circuit functions, Electrode 2 has beenchosen as an example. However the same descriptions apply to Electrode 1and Electrode 3, and in fact it should be emphasized that thisembodiment permits temperature control of more than one electrode. Inother words two, three, four, or more different electrodes can becontrolled with this device.

10B in the figure represents Electrode 2. As can be seen by 11B, and12B, a temperature sensor is incorporated into the electrode thatreports the temperature at the electrode tip, as well as a means forapplying the high frequency energy to the electrode. Temperature isreported via 21B to Control 2, identified by 30B in the figure. Control2 also has an input identified as set temperature 20B, and comparesthese two signals to determine whether to open or close switch S2(identified by 50B). It is important to note that S2 is a generic switchand can be achieved both electrically and/or mechanically and/oroptically. The High Frequency energy in, represented by 40B in thefigure, is therefore connected and disconnected to Electrode 2 viaswitch S2. As switch S2 is opening and closing via Control 2, (which isconstantly comparing the user set temperature to the reported electrodetip temperature and determining whether to deliver HF energy toElectrode 2), a feedback circuit is established which will maintain theElectrode 2 temperature at the user set temperature.

In FIG. 4, another exemplary embodiment of the user interface isillustrated. As identified by 10D and 40D, it is clear that electrodetemperature and/or other pertinent parameters need not be displayed on atwo-dimensional screen. These could be represented, for instance, by LEDor LCD digits. 30D again represents a two-dimensional graphics display,in this case displaying temperature. Again, a graphics display is notnecessary to realize the presently described system and method. Todemonstrate exemplary options for user interface, the mode selector hasbeen represented by a series of buttons that are associated withindicator lights identified as 20D in the figure and Set temp has beenidentified as up/down arrows as shown by 50D. The electrode outputs havebeen schematically represented by 60D.

In FIG. 5, additional exemplary embodiments of the device are shownwhere, this time, the mode selector 20E has a position for EMG inaddition to a high frequency energy delivery position. On thetwo-dimensional display, an EMG signal can be represented, thusidentifying electrophysiological activity of a nerve before and/or afterthe high frequency treatment. For completeness, 60E identifies theelectrode outputs, were once again three have been illustrated, althoughany number greater than 1 is possible with the present system andmethod. The Set temp user interface has been represented in this diagramas a knob 50E, though as mentioned earlier there are other contemplatedways to achieve this user interface. 40E identifies the actual settemperature. 10E is indicating that the temperature displays of theelectrodes (--) is not relevant since they would indicate bodytemperature (37 C), though this temperature could be displayed ifdesired.

FIG. 6 is an exemplary embodiment showing a sensory stimulation graph30F, being displayed on the device. In this particular diagram, eachelectrode has associated with it a thin line and a fat line 35Findicating pre- and post-stimulation sensory thresholds for eachelectrode. Again, there are many contemplated ways that these parameterscould be represented, and this is just an example of one of many ways inwhich to achieve a representation of these parameters that areidentifiable to the user. The mode select switch, identified as 20F, hassettings for both high frequency energy and stimulation. The dashes(--), indicated by 10F in the figure, represent temperature, which isirrelevant in this mode, since with no energy delivery there is notherapeutic heating and all of the electrodes will be reading bodytemperature (which could of course be displayed. The electrode outputs,represented by 60F, once again indicate three connections though anynumber of electrodes greater than one should be covered within the scopeof this inventions contemplated. Set temp is represented by 5F in thefigure, and its associated value is represented by 40F in the figure andis depicted as a two digit display.

FIG. 7 is another exemplary embodiment. Illustrated is a mode selectbutton, 10G, which allows the user to select between EMG, HF, andstimulate modes. When stimulate or EMG mode is selected, a digit(s)represented by 90G, indicates which electrode is selected, as in thesemodes it is important to select one electrode at time, and to know whichelectrode is selected. The electrode selection is made by the knobidentified as 50G in the figure. In this particular embodiment, the userset temperature is identified as a knob indicated by 30G, and the settemperature value is represented by 80G in the figure, and isincorporated within a two-dimensional graphics display 20G. A time vs.temperature graph is indicated by 110G in the figure, and the individualelectrode temperatures, if HF is selected on the mode select, isindicated by 100G in the figure. 40G once again indicates three outputs,and 70G represented by the dotted lines indicate that more than threeelectrodes, or less than three electrodes (as long as number ofelectrodes is greater than one), is contemplated. 60G identifies a logbutton. This button is used in stimulate mode, since the user mustidentify what stimulation voltage threshold is to be saved for futuredisplay.

While the disclosure has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the disclosure. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the disclosure without departing fromthe essential scope thereof. Therefore, it is intended that thedisclosure not be limited to the particular embodiment disclosed as thebest mode contemplated for carrying out this disclosure, but that thedisclosure will include all embodiments falling within the scope of theappended claims.

What is claimed is:
 1. A device for use in delivering therapeutictreatment to a plurality of nerve locations comprising: a radiofrequency energy source having an RF output; a plurality of electrodeoutputs operably coupled to the RF output, wherein each of the electrodeoutputs is separately and individually connectable through acorresponding electrical conductor to a probe; a plurality oftemperature sensor inputs, each of the plurality of temperature sensorinputs configured to receive temperature information from at least onetemperature sensor incorporated into the corresponding probe; and a userinterface for individually selecting a plurality of user-settabletemperatures, each of said plurality of temperatures associated with acorresponding one of the plurality of the electrode outputs, the devicebeing configured such that energy delivery from the radio frequencyenergy source to each of the plurality of electrode outputs is regulatedto simultaneously maintain each of said user-settable temperatures. 2.The device of claim 1, further comprising a plurality of probes, each ofthe plurality of probes coupled to a corresponding one of the pluralityof electrode outputs, wherein the user-settable temperature maintainedfor each of the plurality of electrode outputs comprises a temperaturemeasured by a temperature sensor at a tip of the corresponding one ofthe probes.
 3. The device of claim 2, wherein the electrode outputsinclude the temperature sensor inputs.
 4. The device of claim 2, furthercomprising a plurality of temperature displays corresponding to theplurality of temperature sensor inputs.
 5. The device of claim 1,further comprising a plurality of sensor inputs configured to receivetemperature information from a plurality of temperature sensors at acorresponding plurality of electrode tips.
 6. The device of claim 1,further comprising a plurality of probes, each probe comprising aninput, and an electrode tip, and wherein each probe input is coupled toa corresponding one of the electrode outputs.
 7. The device of claim 6,wherein the probes are at least partially electrically insulated over atleast part of a shaft of the probes.
 8. The device of claim 6, whereinthe plurality of probes are separate and not connected to one another.9. The device of claim 1, further comprising a plurality of indicatorscorresponding to the plurality of electrode outputs, to indicate that aprobe is receiving energy from the radio frequency energy source. 10.The device of claim 9, wherein the indicators comprise indicator lights.11. The device of claim 1, further comprising a set temperature displayto display the temperature set by the user.
 12. The device of claim 11,wherein the user interface comprises a plurality of temperaturecontrols, each temperature control corresponding to one of the pluralityof electrode outputs.
 13. The device of claim 11, further comprising aplurality of temperature sensor inputs, each of the plurality oftemperature sensor inputs configured to receive temperature informationfrom a temperature sensor incorporated into one of the probes.
 14. Thedevice of claim 13, further comprising a plurality of individualelectrode temperature displays corresponding to the plurality oftemperature sensor inputs.
 15. The device of claim 1, further comprisinga graphics panel configured to display at least one of the operatingparameters of the device.
 16. The device of claim 15, wherein thegraphics panel is configured to display the temperature of a pluralityof electrode tips.
 17. The device of claim 15, wherein the graphicspanel is configured to display both the temperature of a plurality ofelectrode tips, and the temperature of a plurality of electrode tipsversus time.
 18. The device of claim 1, wherein the RF output providespulsed high frequency energy.
 19. The device of claim 1, furthercomprising a reference electrode to provide a path for return currentfrom two or more probes.
 20. A system for use in delivering therapeutictreatment to a plurality of nerve locations via a plurality of probes,the system comprising: a radio frequency energy source having an RFoutput; a plurality of separate probes which are not connected to oneanother, each of the plurality of probes comprising an electrode tip,and a temperature sensor to provide information regarding temperature ofthe electrode tip; a plurality of electrode outputs coupled to the RFoutput, wherein each of the electrode outputs is configured to receivetemperature information from and provide radio frequency energy to acorresponding one of the probes, wherein the system is configured toregulate energy delivery from the radio frequency energy source to eachof the plurality of probes to simultaneously maintain the temperaturereported by the temperature sensor of each of the probes.
 21. The systemof claim 20, further comprising a plurality of temperature displayscorresponding to the temperature information received at each of theelectrode outputs.
 22. The system of claim 20, further comprising a userinterface for selecting a user-settable temperature individuallyassociated with any of the electrode outputs.
 23. The system of claim20, wherein the feedback control circuitry comprises a plurality offeedback control circuits each corresponding to one of the plurality ofelectrode outputs.
 24. The system of claim 20, further comprising areference electrode to provide a path for return current from theplurality of probes.
 25. A device for use in delivering therapeutictreatment energy to a plurality of nerve locations via a correspondingplurality of probes, the device comprising: a plurality of electrodeoutputs, wherein each of the electrode outputs is adapted to receivetemperature information from and provide RF energy to one of the probes;a mode select interface configured to select from a plurality ofsettings, wherein, a therapeutic mode setting of the mode selectinterface is a selection of power at an RF frequency for coupling to anyof the plurality of electrode outputs and a stimulate mode setting is aselection of power at a stimulate frequency, which is lower than the RFtherapeutic frequency; and a user interface for selecting auser-settable temperature associated with any of the electrode outputsfor use during therapeutic mode, the device being configured such thatpower at the RF therapeutic frequency to each of the plurality ofelectrode outputs is regulated to simultaneously maintain an associateduser-settable temperature of each of the plurality of electrode outputsat the probe connected to the corresponding electrode output.